A portable device is a terminal that supports various functions based on mobility. Portable devices have been used widely to their convenience of a use and portability. The portable device provides various input schemes for providing user functions. For example, a conventional portable device supports input of given characters or numerals through a key pad mechanically disposed at one side thereof. Further, a size of the portable device can be reduced to improve portability. To secure the suitable size of a display unit in a small portable device, a key pad is removed and a touch screen that includes a touch panel is provided on the display unit.
A portable device outputs various screen configuration elements supporting various user functions recognized by a user on the display unit. Such a screen configuration element can be output in a specific form, such as a text, icon, or image form based on a background image. The screen configuration element is output to have a constant expression value. However, there is a high possibility that a screen configuration element may be obscured by the background image, such that the screen configuration element cannot effectively display information.